A T cell receptor (TCR) that recognizes the NY-ESO-1 (ESO) tumor/testes antigen has been cloned into a retrovirus and can be used to genetically modify human peripheral blood lymphocytes (PBL) so they recognize HLA-A2+, ESO+ tumors. PBL expressing the anti-ESO TCR have been administered with aldesleukin with or without ALVAC vaccine to 21 patients with melanoma following lymphodepleting chemotherapy at the Surgery Branch, resulting in objective tumor regression (complete or partial regression) in ten patients (47%). In animal models using murine cells and in experiments with human T cells in vitro, T cell subsets expressing the lymphoid homing and differentiation marker CD62L, including naive T cells (TNaive), stem cell memory T cells (TSCM), and central memory T cells (TCM), were shown to have superior attributes compared to whole PBL and CD62L- PBL for adoptive cell therapy, including superior persistence following transfer in vivo. despite an abundance of preclinical and retrospective human data suggesting that transfer of less differentiated T cell subsets is associated with superior treatment outcomes, these findings have yet to be confirmed prospectively in patients. Thus, it is presently unknown which PBL subset represents the optimal choice for adoptive T cell therapies. Therefore, in this project we propose to test whether the use of CD62L+-derived lymphocytes engineered with the anti-ESO TCR using currently available GMP-compliant reagents can produce a safe and effective autologous T cell product for use in melanoma patients. We currently have developed a strategy to enrich for and transduce CD62L-derived lymphocytes using GMP quality reagents. Based on these data, we have initiated a phase II clinical trial (CRC protocol 14-C-0058, Phase II Study of CD62L+-derived T lymphocytes transduced with a T Cell Receptor Recognizing the NY-ESO-1 Antigen and Aldesleukin Following Lymphodepletion in Patients with NY-ESO-1 Expressing Melanoma ) in an attempt to assess whether less differentiated T cells might mediate superior T cell persistence and antitumor responses following adoptive transfer into patients with stage IV metastatic melanoma. This trial is now actively accruing patients. Since our last report, we have treated and followed up several patients. We plan to continue enrolling to test our clinical hypothesis during this next fiscal year.